1. Field of the Invention
The present invention relates to a method for processing a duplexed document, and, more particularly, to a method for reducing show-through in a scanned duplexed document.
2. Description of the Related Art
Consumers may utilize a simple photocopying device to make copies of documents coming from a variety of sources which include a variety of mass print media, such as magazines and newspapers. Due to the large volume of these materials, magazine and newspaper producers typically print on low cost, low-grade thin paper stock. To further control costs, the media, e.g., paper, are typically printed in a duplex fashion, i.e., content is printed on both sides of the media, which will be referred to herein as a “duplexed document.” As used herein, the term “front side” is used to refer to the side of the media that is facing the scanner of the photocopying device, and the “back side” is the side of the media opposite to the front side.
Due to the thinness of low-cost media, such media are not completely opaque. Therefore, in addition to sensing the intended document information from the front side of the duplexed document, the scanner sensor of the photocopying device may also sense document content that is printed on the back side of the duplexed document. The photocopy will therefore include both intended information, and unintended information commonly referred to as “show-through.”
A known technique for detecting the show-through effect requires the user to scan both sides of the document. Once the pixel locations of undesirable show-through image information have been detected, methods of removal of the back-side show-through information from the front-side desired document can then be employed.
Such techniques have multiple drawbacks. For example, one drawback is that the duplexed document must be flipped over to face the scanner sensor, requiring either the use of complex and expensive duplexing hardware, or an undesirable user intervention to provide the necessary document flipping. As another example, such a technique typically requires a complicated algorithm to then spatially correlate the dual-side scanned information to account for both the horizontally flipped relationship between the two scans and the misalignment of the two images.